The field of the invention is, in general terms, that of motor vehicle lamps. In this field, different types of lamp are known, amongst which there are in particular:                sidelights, of low intensity and range;        low beam, or dipped beam, headlights, of stronger intensity and with a range on the road close to 70 metres, which are used mainly at night and whose light beam distribution is such that it makes it possible to not dazzle the driver of an oncoming vehicle;        high beam headlights, and additional long-range or fog light type lights, whose field of vision on the road is close to 200 metres, and which must be switched off when another vehicle is oncoming in order to not dazzle its driver.        
Furthermore, certain advanced lamps are known, referred to as dual-mode lamps, which combine the low beam headlight and high beam headlight functions: to that end, there is inside the dual-mode lamp a screen, consisting for example of a removable metal plate, capable of changing on command from a first position in which it does not mask the light signal produced by the light source of the lamp, the range of the lamp then corresponding to that of headlights, to a second position in which it masks part of the light signal produced by the light source of the lamp, the range of the lamp thus being limited to that of low beam headlights.